5.4 dre technologies

Implemented by the ACP Group of States Secretariat

Funded bythe EU

Distributed Renewable Energy (DRE) technologies overviewEMANUELA DELFINO / DIS / Design Department / Politecnico di Milano

LEARNING RESOURCE 5.4

Distributed Renewable Energy technologies

Emanuela Delfino/ Politecnico di Milano / Design Department / DIS

CONTENTS

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1. SOLAR ENERGY

– Photovoltaic system

– Water Heating system

2. WIND ENERGY

3. HYDRO ENERGY

4. BIOMASS ENERGY

– Biogas Digester

– Biomass Gasifier

5. ENVIRONMENTAL IMPACT (LCA) OF RENEWABLE ELECTRICITY



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Types of Renewable Energy

GEOTHERMAL

HYDRO

WAVE

WIND

TIDAL

BIOMASSSOLAR



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………

Solar energy is the most abundant of REs resources and is available

at any location.

1. Solar Energy



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1. Solar Energy

The total solar irradiation of the sun is about 50 million GW which is 10.000 times more than the energy used by the world population



WATER HEATING SYSTEMS

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1. Solar Energy: technologies

SOLAR HEAT

HEATED WATER

PHOTOVOLTAIC SYSTEMS

SOLAR RADIATION

ELECTRICITY



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Source: Africa Biogas CompanySource: Ashden Why solar is super?

1. Solar Energy: photovoltaic systems

https://www.youtube.com/watch?v=_l0PeV7DXog&index=2&list=UUi0mRuqoEGRpJ7zByjfalQg



THE PHOTOVOLTAIC PHENOMENON

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Solar Photovoltaic systems (SPV)

convert the energy from the sun

with solar cells: the PV effect

phenomenon is related to the

electromotive force that is generated

under the action of light in the

contact zone between two layers of

semiconductor, usually silicon-

based .



PV CELLS MATERIAL

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MONO-CRYSTALLINESILICON

(mono-c-Si)

High purity degree purity ingots Performance: 15-18% Cells are rigid and fragile. Size: 2,54 to 5,08 cm, 10 cm, 12.7-15.24 cm

POLY-CRISTALLINESYLICON

(poli-c-Si)

Lower purity ingots (from

waste silicon from the

electronics industry), cheaper

but lower performance.

Performance: 11-14 %

Cells are rigid and fragile.

Size: 2,54 to 5,08 cm, 10 cm,

12.7-15.24 cm

AMORPHOUS SILICON

(a-Si)

Non-crystalline

structure Cheaper to

manufacture and install,

but lower return.

Performance: 5-10 %

Flexible cells.

Free sizes

The most reliable technology available on the market and is the silicon solar cell.



THE PHOTOVOLTAIC PANEL

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A number of solar cells are

gathered together to form a

solar module:

More modules can be combined

to form a field/array with high

degree of modularity and

scalability



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• Photovoltaic Cell/Module

To convert solar energy in electric energy through the photovoltaic effect

• Charge Controllers

To protect and regulate the charge of batteries, interrupt the photovoltaic

field when the battery is charged and prevent

• Rechargeable Battery bank

To store the surplus of solar energy if not connected to the grid

• Inverter

To convert the DC from the photovoltaic modules in AC (necessary for

products such as appliances, computers, cars, urban lights, etc.)

• Breaker box

To distribute electrical current to the various circuits (if grid connected)

• Electric meter

To measure electric energy delivered to their customers for billing purposes

• Wires/cables

SPV SYSTEM COMPONENTS



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TYPICAL SPV SYSTEM LAYOUT

1. STAND ALONE OFF GRID (WITH BATTERIES)



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TYPICAL SPV SYSTEM LAYOUT

2. GRID CONNECTED



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DESIGN / ASSESSMENT

Solar radiation is available at any location

The value of solar radiation depends on:

• The location (higher values closer to the Equator)

• 1400 to 2300 kWh/m2 in Europe and US• around of 2500 kWh/m2 in Tanzania, East Africa

• Period of the year (seasonal climatic variations)• Higher during warmer than in cold months• Higher during the dry season then rainy season

Databases are available to obtain an estimation of annual plant productivity

• Photovoltaic Geographical Information System (PVGIS) • IRENA's Global Atlas

No Data • Weather Modeling and Forecasting of PV Systems Operation

(radiometers)



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SPV SYSTEM POWER DIMENSION AND NUMBER OF USERS

PICO PV SYSTEM HOME PV SYSTEM COMMUNITY PV SYSTEM

1-2 PRODUCTS 1 HOUSEHOLD 2-400 HOUSEHOLDS

1-10 W 10-200 W 200-5000 W



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COSTS

Prices of SPV generation are• in developed market around 2.5 €/Wp• in emerging markets below 1 €/Wp

Stand Alone PV system

Family of 4-5 members

4.2 kW

5355 kWh/year - 35 m2

50000-100000 €

Solar Lanter

4+ hours of light

1-10 W

25-80 €

Solar Home Kit

10-20 hours of light,

recharging batteries

80-200 W

80-350 €



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Solar water heating (SWH) is the conversion of sunlight into renewable

energy for water heating using a solar thermal collector.

It can be used to heat domestic hot water which promotes hygiene and

health, for space heating (e.g. solar driers and greenhouses) etc.

1. Solar Energy: water heating system



These systems are composed of solar thermal collectors, a storage tank

and a circulation loop.

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HOW IT WORKS


Source Image: http://www.ashden.org/technologies



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TYPES OF HEATERS


1. Integrated

collector storage

(ICS or Batch Heater)

2. Active systems with

pumps to circulate water

or a heat transfer fluid

3. Passive systems

with circulating water or

a heat transfer fluid by

natural circulation



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COMPONENTS

Absorber• metal, • High conductivity• High absorptivity• Low emissivity

Copper/Steel with covered with

chromo, alumina-nickel, Tinox

Transparent coverage

• to reduce heat losses • to maximize the efficiency of

the collector

Circulating tubes• metal with good conductivity

The flat and closed collector

Insulating systems• Low Thermal Conductivity• Resistant to high temperatureRock wool, polyurethane foam, polystyrene ...



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2. Wind Energy

Wind energy is site specific. A wind power generator (WPG) converts

kinetic energy of the wind into electric power through rotor blades

connected to a generator.



The force of the wind turns the

blades, converting the energy

of the wind into mechanical

energy of the rotating shaft.

This shaft is then used to turn a

generator to produce electricity

or to operate a mechanical

pump or grinding mill.

Most modern wind turbines are

used for electricity generation.

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2. Wind Energy

HOW IT WORKS



There are two basic designs of

wind electric turbines:

• vertical-axis, or "egg-beater"

style

• horizontal-axis (propeller-

style) machines

Horizontal-axis wind turbines are

most common today

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2. Wind Energy

HOW IT WORKS

Source Image:

http://www.hillcountrywindpower.com/wind-basics.php



- a rotor, or blades, which

convert the wind's energy into

rotational shaft energy;

- a nacelle (enclosure)

containing a drive train, usually

including a gearbox and a

generator;

- a tower, to support the rotor

and drive train;

- electronic equipment such as

controls, electrical cables, ground

support equipment, and

interconnection equipment.

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2. Wind Energy

WIND POWER SYSTEM COMPONENTS

Source Image:

http://www.hillcountrywindpower.com/wind-basics.php



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2. Wind Energy

WIND POWER GENERATOR DIMENSION

Energy need for a family: ca. 5 kW• Micro-Wind generator• Tower height 9 meters • Blades (or rotators) diameter 3

meters



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2. Wind Energy


Energy need for a farm or an isolated group of houses: ca. 60-75kW• Mini-Wind • Tower height 10-20 meters • Blades (or rotators) diameter

15 meters



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2. Wind Energy


Energy need for 200 families: from 600 kW• tower height 50-100 meters • 2/3 blades (or rotators)

diameter 50-100 meters



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2. Wind Energy

DESIGN / ASSESSMENT

Wind power is site specific

Energy produced depends on wind speed at the site:

• Wind speed is highly influenced by topography and obstacles

Wind power changes during the day, and the seasons.

• Wind speeds of 4-5 m/s are required to achieve economic

sustainability

Data all along the year are required.

• Direct measure can be taken with meteorological towers with

anemometers and wind vanes to have speed and directions

• Secondary data can be taken from other measuring

meteorological or airport installations, together with appropriate

calculation models



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2. Wind Energy

COSTS

The price depends on the size, material and construction process.

• Costs of Small Wind systems include• turbine and components: tower or pale, battery storage,

power conditioning unit, wiring, and installation• Maintenance: turbine requires cleaning and lubrication, while

batteries, guy wires, nuts and bolts, etc. require periodicinspection

• Costs depend on the cost of local spares and service• overall costs are in the range 3000 – 6000 €/kW

User 1 family household

Power 5 kW Micro Wind

Cost From 15.000-30.000€



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3. Hydro Energy

Hydro resources are site specific. Hydro power plants transform

kinetic into mechanical energy with a hydraulic turbine.



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The power available in a river or

stream depends on the rate at

which the water is flowing, and

the height (head) which it falls

down.

Mechanic energy drives devices

or is converted in Electric

Energy via an electric generator.

Electricity production is

continuous, as long as the

water is flowing.

3. Hydro Energy

HOW IT WORKS




• Weir and intake channel

where water is diverted from the natural

stream, river, or perhaps a waterfall

• Forebay tank

Artificial pool to contain water

• Penstock

Canal to bring water to the turbine

• Power Group:

the turbine converts the flow and

pressure of the water into mechanical

energy. The turbine turns a generator

connected to electrical load, directly

connected to the power system of a

single house or to a community

distribution system

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3. Hydro Energy

HYDRO POWER SYSTEM COMPONENTS




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3. Hydro Energy

DESIGN / ASSESSMENT

Hydro resources are site specific Hydro Power is the most mature REs technology and has conversion efficiency up to 90%

• Best geographical areas: presence of perennial rivers, hills or mountains

• the right combination of flow and fall is required to meet the desired load

• a river flow can vary greatly during the seasons• detailed information are required to estimate production potential• infrastructures are required: a canalization system is necessary to

send the flow to the turbine and a building to protect the generator

• require low maintenance



Hydro Power plant costs depend on:• site characteristics, terrain and accessibility• (for micro-systems) the distance between the power house and

the loads can have a significant influence on overall capital costs• the use of local materials, local labor, and pumps• operational costs are low due to high plant reliability, proven

technology• overall costs are in the range ca. 3000 €/kW

3. Hydro Energy

DIMENSION AND COSTS

User/energy need Power/ dimension Cost

1 family household 1 kW Family-Hydro ca. 3.000€

3-5 families household 3-5 kW Pico-Hydro ca. 9.000-15.000€

5-100 families connected

5-100 kW Micro-Hydro ca. 15.000-300.000€



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4. Biomass Energy

Bioenergy is made available from materials derived from biological

sources. Biomass is any organic material which has stored sunlight

in the form of chemical energy.

Source Image: Africa Biogas Company



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4. Biomass Energy: biogas digester

Biogas, a mixture of methane and carbon dioxide, is produced by

breaking down wet organic matter like animal dung, leftover food or

human waste.

Image Source: Africa Biogas Company



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Source: Africa Biogas CompanySource: Ashden Why biogas is brilliant?


https://www.youtube.com/watch?v=Ey8nEPqhkhE&index=1&list=UUi0mRuqoEGRpJ7zByjfalQg



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• A large container to hold the mixture of decomposing organic matter and water (which is called slurry)

• another container to collect the biogas

• Opening to add the organic matter (the feedstock)

• Opening to take the gas to where it will be used

• Opening to remove the residue.

In fixed dome biogas plants (the most common type), the slurry container and gas container are combined.

HOW IT WORKS




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Anaerobic digestion of organic

matter produces a mixture of

methane (CH4) and carbon

dioxide (CO2) gas that can be

used as a fuel for cooking,

lighting, mechanical power

and the generation of

electricity replacing firewood or

other fuels

APPLICATION



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TYPE OF BIOGAS DIGESTER

1. Floating Gas Holder 2. Fixed Dome

3. Flexible Bag



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The cost of biogas plants varies greatly from country to country, depends on:

- the costs of both materials (brick, concrete and plastic)

- labor can be very different

The cost per cubic meter of digester volume decreases as volume rises.

Using plastic or steel to pre-fabricate biogas plants usually increases the material cost but can substantially reduce the labor needed for installation.

DIMENSION AND COSTS

No. of family members (cooking and lighting requirement)

3-4 members 18-24 members

Size of digester 1 m3 6 m3

Av. Daily Fresh Bovine Dung and Slurry Requirement

25 kg 150 kg

Number of Cattle 2-3 12-18

Cost / Cost Tubular Type 150 € 355 €



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4. Biomass Energy: biomass gasification

Gasification is a process that

converts biomass through

partial combustion in the

presence of a limited supply of

air into a combustible gas

mixture known as producer gas

(sometime called ‘wood gas’).



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In small-scale gasifiers, the reactions take place in a stationary or fixed ‘bed’ of biomass, a closed vessel, cylindrical in shape.

It takes place in four stages:

• Drying

• Pyrolysis

• Reduction

• Combustion

HOW IT WORKS


Updraft gasifier:

Air blown in at the bottom

Gas contaminated by tar and too dirty for internal combustion engine

Downdraft gasifier:

Air is drawn downwards through the biomass

Cleaner gas



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Source: Africa Biogas CompanySource: Ashden Husk Power Systems, electricity from crop waste


https://www.youtube.com/watch?v=d0XcoeqVoaI



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4. Bio-Energy: biomass gasification

Initial capital cost to buy/build the gasifier

• €1,500 per kW (electrical) for plants up to 100 kW

• €1,200 per kW for plants between 100 kW and 1000 kW

Running costs to maintain the gasifier

• €0.05 per kWh generated

The cost of a 1 kW Husk Power systems for 1 family is around 1.500€ or lower.

COSTS



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5. Environmental impact

Is Renewable Energy zero impact?



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5. LCA comparison of some renewable and non-renewable energy systems

Method: Eco-indicator 99 (H) V2.07 /Europe EI 99 H/A / Single score

RENEWABLE ENERGY SYSTEMS NON-RENEWABLE

ENERGY SYSTEMS

1kWh electricity



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TOTAL REDUCTION OF

99%

1kWh electricity




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TOTAL REDUCTION OF

90%


1kWh electricity




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References

- Open Seminar: Distributed Renewable Energy System opportunities for

All, POLIMI and UNESCO, Politecnico di Milano, English, 2014:

• 2.3 Renewable and distributed energy for a local and sustainable

development

• 2.4 Off main-grid systems for access to electricity

• 2.5 Off main-grid technologies for power generation in rural contexts

- Renewable Energy for Unleashing Sustainable Development, E. Colombo, S.

Bologna, D. Masera, 2014

- LeNSes Pilot Course: System Design for Sustainable Energy for All, CPUT,

POLIMI LENSes Team, Cape Peninsula University of

Technology, English, 2014:

• 4.5 Renewable Energy

- Ashden Technologies

- Energypedia

http://lenses.polimi.it/index.php?P=lr_upload_course.php&ID=NTQQRXWPOH20110310103752&DWNL=Y

http://lenses.polimi.it/index.php?P=lr_upload_course.php&ID=NTQQRXWPOH20110310103752&DWNL=Y

http://www.ashden.org/technologies

https://energypedia.info/wiki/Main_Page



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Thank [email protected]

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5.4 dre technologies